The present invention relates to support assemblies for use in mine workings.
In the mining art it is well known to employ support assemblies with hydraulic telescopic props carried on floor-engaging means and capable of being braced between the floor and roof of a mine working. A common roof cap can be mounted at the upper ends of the props. A series of such assemblies would normally be arranged alongside a scraper-chain conveyor and shifting rams would then connect the assemblies to the conveyor to enable each assembly and an associated portion of the conveyor to be moved up alternately to follow the mining progress.
It is also known to provide a goaf shield at the goaf side of the assembly to screen off the assembly from the goaf or stowage zone. The goaf shield is arranged to displace as the props extend or retract and it is generally desirable to provide a so-called lemniscate guide system which maintains the orientation and horizontal position of the roof cap so that the roof cap moves in a vertical sense with no significant longitudinal displacement when the props are operated. In this way the forward end of the cap nearest the mineral face moves in a vertical line. An example of such an assembly is described in German patent specification 2217830.
The known forms of support assembly suffer from a number of disadvantages. In order to prevent deformation forces from acting on the guide system and goaf shield the one piece floor-engaging means is usually a rigid heavy torsion-resistant structure which is costly to manufacture. Moreover the one-piece floor structure is not always able to cope with irregularities in the level of the floor. The goaf shield is usually designed to completely screen off the working zone from the goaf or stowage zone and any accumulation of debris or other material in the support region can cause problems during shifting of the support assembly.
A general object of the present invention is to provide an improved support assembly for a mine working.